GPUExtensions: GL backend isolation

This is part of the Vulkan task T68990.

This commits changes a few things:
- Rename extensions to capabilities (but left the file name untouched).
- Cubemap mip render workaround detection is rewritten using gl
  commands to avoid using the GPU API before initialization.
- Put all the capabilities that are only relevant for the GL backend
  inside GLContext as static variables.
- Cleanup the names of the limit variables.
- Separate all GL related workaround search inside the GL module.

2 files changed, 0 insertions, 6 deletions

diff --git a/source/blender/draw/intern/DRW_render.h b/source/blender/draw/intern/DRW_render.h
index 680636f9e87..e154a52b32f 100644
--- a/source/blender/draw/intern/DRW_render.h
+++ b/source/blender/draw/intern/DRW_render.h
@@ -721,7 +721,6 @@ void DRW_state_lock(DRWState state);
 void DRW_select_load_id(uint id);
 
 /* Draw State */
-void DRW_state_dfdy_factors_get(float dfdyfac[2]);
 bool DRW_state_is_fbo(void);
 bool DRW_state_is_select(void);
 bool DRW_state_is_depth(void);
diff --git a/source/blender/draw/intern/draw_manager.c b/source/blender/draw/intern/draw_manager.c
index 09ce16efcc2..49780f59db3 100644
--- a/source/blender/draw/intern/draw_manager.c
+++ b/source/blender/draw/intern/draw_manager.c
@@ -2496,11 +2496,6 @@ void DRW_draw_depth_object(
 /** \name Draw Manager State (DRW_state)
  * \{ */
 
-void DRW_state_dfdy_factors_get(float dfdyfac[2])
-{
-  GPU_get_dfdy_factors(dfdyfac);
-}
-
 /**
  * When false, drawing doesn't output to a pixel buffer
  * eg: Occlusion queries, or when we have setup a context to draw in already.